Friction draft gear



Oct. 49

J. R. CARDWELL FRICTION DRAFT GEAR File y 25, 1926 JZz Y/ JEWE on. a, lea-7.

ti i ST E S caries.

JAMES R. OARDWELL, or oHIoAeo, ILL'Il-NOIS, assianon ro nit-Ion.nnarrcnanucom PANY, OF CHICAGO, ILLINOIS, A CORPORATION;OFJDELAWAREJ FRICTION nnar r snare;

Application filed May 25,

vii proved gear applied thereto;

Figs. 2 and 3 are views in perspective of two of the elements of the gear.

While the invention has wider applicability, it'is primarily intended for use in connection with the Cardwell gear which has been in common. use in the railroads of this country for many years.

This gear comprises a pair of chambered followers 10, 10, usually seated as shown against plate followers 11,11, which cooperate respectively with the bufling lugs 12 and the draft lugs 13 attached to the center of draft sills 1 1 of the car; a tension rod 15 extending transversely through the sills 1 1 and carrying upon each of its end portions helical springs 16 and 17, which react be tween seats as 18 attached to the extreme ends of the rod and seats 19, mounted slidingly upon the rod and bearing through sleeves 20 upon a pair of wedging element-s 21 and 22, sleeved upon the rod, a central double headed wedging element 23 sleeved upon the rod and two pairs of triangular wedge blocks 24, 25, which seat against the end faces of the followers 10 and project between the elements 21 and 22 and the element 23, engaging inclined or wedging faces thereof.

Upon the compression of the gear,the advancing follower forces the triangular wedge blocks associated with it forwardly, spreading the side wedging elements 21 and 22 against the resistance of the springs 16 and 17, and carrying forward the rod 15 and the wedging elements sleeved upon it, and thus causing the triangular blocks associated with the stationary follower to cooperate in the spreading action of the elements 21 and 22.

It is essential that the sleeved wedging elements have adequate strength to preventfracture and it is further essential, because of the limited space available, thatthese elements be restricted in size as much as possible. To this end it has been the practice to recess the sides of the central element 23,

1926. Serial No. 111,517.

ing these ribs extending to the edges of the wedging elements and being formed in the inner portion of the wedging or inclined face of the element, of which the surface of the rib 27 forms a continuation.

The channels, as 30, in the element 23 are formed within'the end walls of its lateral recesses and extend or open through its wedging faces, as 31, leaving ribs,.as 32, 33,

extending from the channels to the margins oft-he element.

VVhen the gear is assembled the ribs 27 enter, upon release, into the channels 30 and the ribs 32, 33, into channels 28, 29.

By reason of this configuration of the adjacent faces of the elements 21, 22 and 23, their wedging faces may be prolonged with out limiting the inward movement of the elements 21, 22, due to the spring pressure. This extension of the wedging surfaces adds very materially tothe efficiency of the gear by increasing the area of frictional surface of the member 23, this increase being available as the gear approaches the limit of its compressive movement, at which time the maximum frictional resistance is desirable. The member 23 withstands by far the greater part of the load imposed by the c'ompression of the gear, as it must overcome not only the resistance of the springs but the heavy frictional resistance due to the sliding of the triangular blocks 25, 26, on the face of the follower, while the members 21, 22, meet the resistance of the springs only.

The central wedging element 23 may be a single casting, as shown, or it may be made of two abutting parts, as shown in Letters Patent No. 1,137,951, granted to me May 1. 1915. In-the appended claim it is referred to as a single element, but it will be understood that inasmuch as when divided its action is the same, the divided form is intended to be included within the claim.

I claim as my invention:

A draft gear comprising a central double end wedge element, such element being late al y recessed and the .end portions of the walls of the recesses being outwardly inclined and longitudinally channeled, a pair of blocks flanking the central element and having faces complementary to the chan neled portion of the walls thereof, such faces being prolonged as wedge surfaces, a pair of wedge blocks cooperating with each end of the central element and the wedge surfaces of the pair of blocks, and spring means urging the flanking blocks toward the cen- 10 tral element. y

In testimony whereof I afiiX my signature.

JAMES R. CARDlVELL. 

